Recently, in the field of endoscope, a swallowable capsule endoscope has appeared. The capsule endoscope is provided with an imaging function and a radio communication function. The capsule endoscope has a function of sequentially picking up images after the capsule endoscope is orally swallowed by a patient for observation (examination) until naturally discharged out of a human body, while passing through body cavities, for example, inside organs such as stomach and small intestine, according to the peristalsis thereof.
Image data obtained inside the body by the capsule endoscope while moving inside the body cavities is sequentially transmitted to the outside by radio communication, and stored in a memory provided in an external receiver. If the patient carries the receiver having such radio communication function and memory function, the patient can freely move even during the period from swallow of the capsule endoscope until discharge thereof. Thereafter, doctors and nurses can perform diagnosis based on the image data stored in the memory by displaying an image of the organs on a display.
Most capsule endoscopes take such a configuration that a driving power is provided by an embedded power supply. Further, some propose a configuration of the capsule endoscope including a lead switch which is provided in the capsule endoscope and turned on and off in response to an external magnetic field and a permanent magnet which is provided in a package covering the capsule endoscope and provides the magnetic field to control the driving of the capsule endoscope. The lead switch provided in the capsule endoscope has a configuration so that the lead switch maintains an off state under an environment in which the external magnetic field having intensity higher than predetermined intensity is applied, and is turned on when the intensity of the external magnetic field is lowered. Therefore, the capsule endoscope is not driven in a state of being packed in the package, and starts being driven when the capsule endoscope is taken out from the package to be released from the influence of the permanent magnet. With such a configuration, it is possible to prevent the driving of the capsule endoscope while the capsule endoscope is packed in the package (for example, see Patent Document 1).    Patent Document 1: International Publication No. WO01/35813 pamphlet